Fluid seals are used to seal between a cylindrical journal such as a crankshaft of an internal combustion engine and a journal case such as a crankcase. The crankshaft is received in a crankcase comprising an engine block (or cylinder block) and a bearing cap fastened to the block. A top half of the crankshaft is received in a generally half-cylindrical shaped opening of the block with a bottom half of the crankshaft received in a mating opening of the bearing cap. A fluid seal is received in both openings between the crankcase and crankshaft and prevents the leakage of engine oil from the engine while permitting crankshaft rotation.
One known fluid seal used in an environment such as the crankcase of an internal combustion engine is a so-called "rope" seal, commonly known as a jute. Typically, a first rope half seal is received in an annular seal groove of the block and a second rope half seal is received in a mating annular seal groove of the cap. Trimming operations are generally required to remove excess portions of the half seals. Finally, the cap is fastened to the block. Until the late 1980's rope seals were formed from woven asbestos and non-asbestos materials. While always difficult to install, the use of asbestos aided in assembly and helped to generally provide an acceptable seal when properly positioned in the crankcase. However, since rope seals have been formed from solely non-asbestos materials, assembly has become even more difficult because the non-asbestos material is much harder and not as pliable.
A second known fluid seal is a split seal. A split seal is made up of two half seals molded to a metal reinforcement. The first half seal is received in a groove of the block and the second half seal is received in a groove of the cap. The cap and block are then fastened together. Such a seal is expensive and difficult to produce, requiring sophisticated tooling and tight tolerances. Additionally, both rope seals and split seals have at least two points of discontinuity where the half seals mate with one another, enhancing the chance for unwanted fluid leakage from the crankcase as the crankshaft rotates.